In general, in an AMT or DCT vehicle using a dry clutch, the clutch may overheat due to continuous slip. Overheating of the clutch may cause a change of characteristics of the clutch and, in some cases, may cause an adverse situation if the clutch is released due to a temporary loss of friction of a clutch disc facing. Since an improvement of characteristics of the facing can be difficult, it is important to control the clutch so as not to cause overheating of the clutch.
Hereinafter, for reference, the term “clutch” means a “dry clutch” unless stated otherwise.
In general, as a slip amount of a clutch increases, a heat generation rate increases. Therefore, when a slip amount of the clutch is reduced, the heat generation rate is decreased. However, if the clutch is connected to a power source, such as an engine or a motor, so as to rapidly reduce the slip amount of the clutch, an impact can be caused. Therefore, in terms of drivability of a vehicle, if a soft feeling needs to be achieved as in starting of a torque converter-type automatic transmission, a method of slowly reducing the slip amount of a clutch is used.
However, if the slip amount of the clutch is slowly reduced on a sloped road, a heat generation rate is greatly increased. Since a presence of a slope corresponds to an increase in a vehicle load, acceleration of the vehicle is decreased and thus the slip amount is more slowly reduced. Consequently, an excessive heat generation rate can result.
The above description has been provided to aid in understanding of the background of the present disclosure and should not be interpreted as conventional technology known to those skilled in the art.